Lately, I’ve been consumed with visions of hamburgers. You see, I recently started a diet, which I never do. I don’t believe in diets. I haven’t dieted since college and have no intention of getting into that vicious cycle all over again.

My new diet isn't about losing weight. It's about challenging my habits and experimenting with different theories around eating to see what I can learn. So, as I restrict myself from eating exactly what I want for the first time in a decade, I’ve been thinking a lot about behavior change. And burgers. To distract myself from my carb cravings, I’ve come up with a theory on how to successfully make big changes:

The key to successfully making a change is to underestimate yourself in the short-term, and overestimate yourself in the long-term.

Let's break that down.

1. Overestimate yourself in the long-term

When it comes to any goal, play big.

Several years ago, I wanted to start running. I had always thought of myself as someone who just couldn't run long distances. But since I couldn't tolerate the idea that I wasn't capable of something I wanted to do, I set out to prove myself wrong.

The first time I ran 3 consecutive miles, I signed myself up for a half-marathon. It was my first ever race-- I had never even run a 5k before. So why jump from 3 miles to 13? Why not start with a 5 or 10k, something I knew I'd be able to do?

Because that's just it: I knew I'd be able to do a 10k. It didn't feel like enough of a challenge, so it didn't excite me. I've written before about the motivating power of fear. Running 10k didn't scare me. Running 21k did.

If your goal doesn't scare you, aim higher.

But here's the thing: the key to aiming high is playing the long game.

I didn't run my first half-marathon the next month; I gave myself 6 months to train properly. Which was another benefit: my goal was sufficiently fear-inducing that it motivated me to take it seriously.

When we aim low and focus on small, short-term goals, we easily get demotivated because without a real challenge, there's no excitement. Plus, if it's quick and easy to do, the pay-off is so much lower. The less you put into something, the less you get out of it.

But when you aim high, work hard and actually achieve what you set out to do, it can be life-changing.

The power in aiming high is that you challenge your limits. When you succeed, you disprove the limits you've set for yourself and the beliefs you have about what's possible.

You’d be surprised how flexible your limits are when you’re willing to push them.

So if you want to make a change, make it big, be both ambitious and patient, and push yourself to achieve things you never thought possible. But not right away.

2. Underestimate yourself in the short-term

This might seem to spit in the face of everything I just said, but there's a time when you should underestimate your abilities. And that time is when you're first starting out on making a change.

So what do you to? In your excitement to get started, you take on too much, too quickly. You start a low-carb diet by swearing off all carbs forever. You start a running practice by telling yourself you’re going to run every single day. And then, when you inevitably skip a day or eat a piece of pizza, you get frustrated, claim it’s impossible and give up.

Which is why underestimating yourself can actually help you make the change you want to make.

Here’s why:

To achieve something, you have to believe it’s achievable, and the only way to do that is to build proof that it’s possible, one small step at a time.

So when you’re first starting out, start small. Make it easy for yourself to succeed, because every small success is proof that you should keep going. Every little win helps you build the confidence you need to believe that it's possible.

Remember, you’re playing the long game. Build a strong foundation by taking it slow at first. Rushing it at the start and setting overly-ambitious short-term goals only sets you up for failure.

It sounds harsh, but there’s actual science behind this tough love. Multiple studies show that most people, especially those “unskilled” at something (i.e. just starting out), have a tendency to overestimate their abilities, especially compared to others.

This means that even though we “know” it isn’t realistic to expect to be able to make a big behavioral change overnight, the vast majority of us still think we’re capable of succeeding where others have failed.

Which, of course, we rarely do.

So how can you beat the trend? How do you know you’re setting realistic short-term goals, when obviously our perception of what’s realistic is skewed?

Aim low. Really low. Take what you think is realistic, and cut it in half.

Yes, really.

Start there, at half of what you think is doable, and if that proves to be too easy, add to it. But first, make sure that it is in fact “too easy” by actually doing it. Remember, you’re in this for the long haul. It’s a whole lot easier to make a big, ambitious change when you’re moving forward, not having to step backwards.

So if you’re considering a life change-- whether it’s starting a new diet or a new career, breaking a bad habit or creating a good one-- aim big, but start small.

You’d be surprised how far you can go by knowing when to hold yourself back.

How do you make lasting changes?Share your advice in the comments below!